Conventionally, for example, Japanese Patent Laid-Open No. 2012-159059 discloses a spark-ignition type engine in which the anodized aluminum coating film is formed on the bottom surface of the cylinder head configuring the combustion chamber, wherein the film thickness of an anodized aluminum coating film is configured to be thinner or the roughness of the surface of the anodized aluminum coating film is configured to be larger, with increasing distance from the center portion of the cylinder head with which an ignition plug is provided. An anodized aluminum coating film has a lower thermal conductivity as compared with the base material (an aluminum alloy) of the cylinder head, and functions as a thermal insulation film with a low thermal capacity per unit volume. By making the film thickness of the anodized aluminum coating film and the roughness of the surface thereof as described above, heat accumulation can be re-strained by reducing the thermal insulating property in the spot away from the ignition plug, and therefore, resistance to knocking which easily occurs in the spot can be enhanced.